Firstly, all praise to Allah, the Almighty, and the Benevolent for His blessings by helpingus to finish the field works, the labs, and the reports of the three labs that we have done. Thisreport is due to the subject Satellite Surveying II.

We would like to thank to our lecturer, Dr. Tajul Ariffin Bin Musa, for providing us a lotof information on how to do this labs and reports. Special thanks also to GPS teaching assistants,Mr. Amir Sharifuddin, Ms. Wan Anom, Ms. Suryati, Ms. Hidayah, Ms. Fazlina and Mr. Yaakubfor their willing to help us to do the field works, labs to process by using Trimble Total Controland Surfer8 Software.

Besides that, we would like to thanks to our friends for their cooperation and sharing theinformation about this field works and labs. We really appreciated their valuable concerntowards us.

Last but not least, thanks to all for their supports. Hopefully, this field works, labs andreport can be useful for us and others for now and in future especially in Geomatic Engineeringstudy.

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The Global Positioning System (GPS) is a satellite navigation system developed andmaintained by the U.S. government. Initially designed for military applications, civilian usershave found numerous applications using GPS. !m m "#$ are start from Radio signals aresent from orbiting satellites to earth and then GPS receivers on the ground can collect andconvert the radio signals into position, velocity, and time information. Some GPS receivers havethe ability to store attribute information in addition to position information. Examples of attributeinformation are the condition of a street sign, the name of a road, or the condition of a firehydrant. Position and attribute information can be stored in a Geographic Information System(GIS) to help users manage their assets more efficiently.

Navigation solution is one of the GPS positioning techniques that give position of theuser in a real time. Main measurement of this technique is code measurement because code canstraight away gives range with using code based receiver. In this case, handheld GPS receiver isthe equipment used as code measurement. Real Time Kinematic (RTK) technique needs a basestation as initialization before the job start. Base station is used to fix ambiguity. At least 4satellites needed in order to fix that ambiguity. RTK technique is almost similar with kinematicbut the difference is in add-on equipment which is radio link. Base station then send thecorrection to the rover via radio link.

Geocaching is a new treasure hunting game. Armed with a Global Positioning System(GPS) device and coordinates, you can locate treasures that others have stashed in unusualplaces. On Geocaching.com you can find the latest stashes in your area, how to hide your ownstash, and information on how to get started in this fun. Geocaching is a recreational new sport inwhich a person/persons hide a container known as a "Cache" using a GPS to read it's placedcoordinates In Geocahcing Game, the task is to find a coin that has been buried using code baseand carrier phase solution.

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m To expose the student about the difference procedures of carrier phase measurement and code phase measurement. m To introduce students with RTK equipment and the procedures to determine point position by using the Garmin Handheld and RTK receiver.

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Location: Helipad (G11)

Date: 6th and 13th August 2009

Time: 3:00pm

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There are two types of instruments that have been used in this Geocahe Game which are: 1)m Code Base Receiver (Handheld Garmin) ± 1 2)m Carrier Phase Based Receiver with RTK System (Unistrong) ± 2 3)m Controller Unistrong ± 2 4)m Tripod ± 1

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m The coordinate of the coin been set up in Handheld GPS receiver.

(03°10¶20.7´N, 101°43¶18.1´) m Select the navigation mode in handheld to get to the point coordinate of the coin that have been set up.

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m Set the base station coordinate (Helipad, G11 ) into RTK system equipment (known point)m m This system is connected with ISKANDAR1 using radio link communicationm m Rover equipment been set up with refer to base station (G11)m m The coordinate of the coin is set up into Rover equipmentm m Moved the rover with refer to the coordinate that has been sent by base station until we reach the coordinate of the coin.m

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1.m GPS handheld been used in the first field work.

2.m Key in the coordinate of the coin that have to be found 3.m This handheld will guide the user about their position and the direction of the coin according to the waypoint displayed. 4.m This Handheld cannot give the accurate position of the coin but it just give the radius of the position 5.m The RTK method is used to get the accurate coin position 6.m GPS receiver been set up at base station (helipad) which is near the coin area 7.m Cable is used to connect the controller and the receiver, and the coordinate of the base station is set up. 8.m Another GPS receiver is used as the rover one. The controller and receiver is connected using Bluetooth function. Base station and the rover is connected with radio link communication. 9.m Set up the coordinate of the coin into the controller of the rover equipment. 10.mInitialization process has to be done to fix the ambiguity before the process of finding the position of the coin. 11.mThe rover equipment is moved according to the direction of the coin coordinate. Controller and receiver move together to avoid the loss of connection between these two devices. 12.mDetermined the coin position and find it.

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Handheld receiver cannot give us the right position of the coin. So, we cannot find thecoin. It is because; the handheld is single receiver that used code phase measurement. Codephase measurement is one processing technique that gathers data via a C/A (coarse acquisition)code receiver, which uses the information contained in the satellite signals (pseudo-randomcode) to calculate positions. This processing technique results is in 1-5 meter accuracy. It cangive the coordinate in real-time but the coordinate using RTK solution is better. Besides that, theaccuracy of the handheld Garmin equipment is 5m so it will give the position in the radius of 5meter.

RTK is using carrier phase which is another processing technique that gathers data via acarrier phase receiver, which uses the radio signal (carrier signal) to calculate positions. Thecarrier signal, which has a much higher frequency than the pseudo-random code, is moreaccurate than using the pseudo-random code alone. The pseudo-random code narrows thereference then the carrier code narrows the reference even more. After differential correction,this processing technique results in sub-meter accuracy

Base station calculates the differences between its known coordinates with the coordinategiven by GPS at that time. Then it will send the corrected coordinate to rover equipment. Butbase station has to be initialized first to fix ambiguity before the process of finding the coin isstarted. At least four satellites needed in order to fix the ambiguity.

Despite the advantages of RTK, it also has its own disadvantages. RTK the rover setcannot be moved very far from the base station to make sure it gets the reliable solution. It isbecause, if the rover is far from the base station, distance dependent error occurred and error willbecome larger. The radio link is also cannot go up to 100km because the radio link needs ³line ofsight´.

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The geocahcing game is a GPS game that makes us more understand on the GPSsurveying. In this game, we have learned more about the concept and the work of navigationsolution by using the Garmin handheld. While by using the RTK receivers, we have learnedmore about the concept and how the RTK surveying work on real-time. We also learn theadvantages of using the RTK surveying such as the surveying works can be done faster, use lessman power thus can reduce the operation cost, can have the point coordinates almost in real-timeand many more.

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m m Due to this task requirement, we have to do GPS observation in order to get the data to becomputed. We managed to complete the job without any major problem. On the other hand, allthe minor problems have been overcome through discussion.

In this computation, we used Trimble Total Control as the software to process the data.Trimble Total Control provides exceptional geodetic control capability plus powerful processingand tools to enable large data sets to be processed extremely quickly with extensive analysis andreporting. It is ideally suited to handling large GPS networks and long baselines. Trimble TotalControl also was designed for fully automated baseline calculation, achieving relative accuraciesof 1 ppm and better depending on ephemeris accuracy. The Static Baseline Estimator performscarrier phase data reduction in two steps:

1. Double difference floats solution

2. Double difference fixed solution

But, in this assignment we only focus on double difference fixed solution. In doubledifference fixed solution, it used to derive optimum phase ambiguities from the float solution atime optimized search technique is applied for the solution with the smallest sum of squaresresidual error. Statistical testing is used to verify the correctness of the ambiguity resolution. Theability for a fixed ambiguity solution is limited by the required minimum ratio of variances forthe Fisher test. Trimble Total Control uses by default a value of 1.8 for static processing. If thefrequency is set to Lc > [x] km, the software will provide 5 different fixed solutions which are:

m L1, L2, Lw, Ln, Lc

If the frequency setting is L1 only or L2 only, the baseline estimator will only use L1 orL2 data and accordingly generate only one fixed baseline solution. Besides that, the resultsobtained from processing GPS observations are baseline vectors (relative coordinates) based onthe World Geodetic System of 1984 (WGS84). These coordinates are three-dimensionalCartesian coordinates, which are defined in an Earth centered, Earth fixed frame.

Here, the baselines and terrestrial measurements are the only observations. No controlpoints are needed to adjust the network. Because no control points or datum restrictions areimposed on the network, the inner accuracy of the measured baseline network is determined.Therefore, this adjustment is called free or unbiased. A baseline or terrestrial measurementcontains only information about the relative position of two points. Because these are the onlyobservations, which enter the adjustment, the absolute position in space of the adjusted networkcannot be determined by the adjustment procedure. Therefore, after the adjustment, one point ischosen as a reference point and the network is shifted onto this reference point. This referencepoint is the first point in the point list.

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Here, baselines, terrestrial measurements and control points in WGS84 are added asobservations to the adjustment. Adjusted baselines, terrestrial measurements and adjustedabsolute point coordinates are calculated.

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m To improve the knowledge on GPS observation planning, technique of observations and

field procedures. m To enhance our knowledge about GPS data processing and how to do the control network in GPS surveying. m To determine the coordinate of a control point to be a base station for the next lab which is Topo Mapping.

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Location: Padang Kawad UTM

Date: 10th September 2009

Time: 4pm ± 6pm

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GPS receiver Unistrong E650R Controller Unistrong E650R

Tripod

m Ground Plane m Tribrach m Hammer m Nail

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Total Trimble Control Software

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m Static (mode) GPS surveying technique.

m Two (2) sessions, A and B. The duration of each session is 1 hours. m Session A from 4 pm to 5 pm. m Switch-off receiver. m Switch-on receiver, and start session B from 5 pm to 6 pm.

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m Make a mission planning. m Set the observation date. m Reserve the transportation on the observation day. m Reserve two (2) units of dual frequency GPS receivers on the observation day.m

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,m IskandarNET 1 (ISK1) in UTM

m The quality of measurement for the coordinate is should be less than 5cm (standard deviation of coordinates < 5cm)m m If the standard deviation of the coordinates are less than 5cm, so it will be accepted and vice versa.m

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Base Setup

1.m Set up the receiver at Atomic control point (Padang Kawad UTM). 2.m Connection between the receiver and the controller was set up and they are connected by bluetooth. 3.m Start the static survey for one hour for the first session. 4.m After one hour, stop the survey and start again the survey for second session with the same setting for another one hour. 5.m Then, download the data that have been collected by the receiver then process the control network by using Trimble Total Control Software.

Steps to Use Controller Unistrong E650R

Step 1

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Note: For session 2 we just stop the survey and continue it again. No need to configure the device.

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Procedure to use Total Trimble Control Software to establish the control network and determinethe coordinate of Atomic Point (ATM1).

1.m Locate all Rinex data for Iska 1, Iska 2,Iska 3 and Atm1 in one folder to make the data processing easier. 2.m Open software Total Trimble Control.

3.m Total Trimble Control was set up by using RSO of Malaysia and EGM 96 format.

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4.m Next, import three Iska data for session 1 to form the baseline.

5.m Click to add to Project and set the antenna type to micro-centered L1/L2 permanent and click OK.

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7.m Then, fix the known point by:

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Note: for one session, we just get two independence baselines only which are baselines ISK1 to ISK2 and ISK1 to ISK3. So, we must disable baseline ISK2 to ISK3 and insert the data of session 2 to create baseline ISK2 to ISK3.

9.m Set up the parameter before process the baselines.

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11.mTo process baseline ISK2 to ISK3, we must fix ISK2 first and step 7 to step 10 is repeated.

12.mIf processing baseline is not passing (yellow baseline appears). We must adjust the baseline by following step below.

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13.mDoing loop closure for checking misclosure then click report to see the value of Misclosure Vector Length.

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15.mThen, click on the report button to see the report of that adjustment. From the report, we can see the quality of the network control.

16.mAfter that, repeat the step 4 to step 15 to make a control network that include of the Atomic Point (ATM1) and from the Adjustment report, we can get the coordinate of the point in the Biased Adjustment report.

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Below shows the results of Loop Closure which is the Misclosure Vector Length = 5.05cm

Coordinate of Atomic Point (ATM1) at Padang Kawad UTM is:

m ±m The figure above shows the network of three stations which is IskandarNET1, ISkandarNET2 and IskandarNET3. For this observation, it divided into 2 sessions, session A and session B. For session A, we fixed station IskandarNET1 as control station and the station IskandarNET2 is fixed as control station for session B. ±m There are 2 sessions needed in processing this control network because we want to make sure the baselines that we process is not dependent to each other. So, in this procedure, the baselines that we have processed are independent.m

m ±m The white baseline showed that we have disabled that baseline in order to process the baseline ATM1 ± ISK1, ATM1 ± ISK2 and ISK1 ± ISK2 to be independence baselines.m ±m The green colour of all baselines means that the baselines are acceptable.m

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±m The residual plots represented of the observation residuals for each satellite used in the baseline solution. It indicated the quality of data received from each satellite. The plot also shows the residuals for each satellite for each measurement cycle. m ±m Noisy satellites may affect data coming from other satellites. The lines on the graph should be centered at zero. The amount of noise in the solution is indicated by how far the plot varies from zero. m

m ±m For the 3D Network Adjustment, the results obtained from processing GPS observations are baseline vectors (relative coordinates) based on the World Geodetic System of 1984 (WGS84). ±m These coordinates are three-dimensional Cartesian coordinates, which are defined in an Earth centered Earth fixed frame. With this adjustment Cartesian point coordinates in WGS84 are calculated from baseline observations and, if any from terrestrial measurements and control points in WGS84.

±m In this result, the quality of measurement of the coordinates also can be seen. The standard deviation values of each coordinate showed the quality of the measurement. ±m This coordinates and height value are accepted as the qualities of measurements are below than 5cm.

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m In order to understand well on how to conduct the processing the data, we decided to make an appointment with Ms. Wan Anom. All the error that occurred during the processing will be overcome together. m Mr. Leong and Ms. Su also helped us during the downloading data from the receiver to the computer. In addition, we also learned how to convert the data in the form of RINEX files. m During the day of our observation, the weather is in good condition. m There are minor problems that occurred during the processing. In the right order to input the data, we should input them one by one. Unfortunately, our data cannot do as follows. We must select all the data to add them to the project. m Besides that, our data cannot be converting through TTC software. So we used RnxTransform software to convert the data to RINEX files. m The carrier phase used for our GPS processing is L1. L1 has wavelength of 19.03cm and frequency of 1575.42 MHz. The reason for choosing L1 is that it has a short wavelength and it is suitable for short baselines. m We used Saastamoinen model. The model compensates errors that are introduced when the signals pass through the troposphere. The amount of correction varies with respect to the satellite elevation. Saastamoinen is ideal for receiver with elevation cutoff of 15 degree. m For the residuals graphical, all above plot shows the residuals for each satellite for each measurement cycle. Noisy satellites may affect data coming from other satellites. The lines on the graph should be centered at zero. The amount of noise in the solution is indicated by how far the plot varies from zero. Through experience, we limit the residuals to not greater than +- 0.02m.

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After tough days trying to finish up all the observation, computation and this report, atlast I have come to the final part of this report. I totally admit that this processing is reallychallenging especially when it comes to the processing part. This is due to the requirement ofusing Trimble Total Control as the software to solve the network observation.

Through this GPS observation, we have been exposed to GPS observation using the staticobservation positioning techniques, GPS signal processing & report writing. Besides, we alsohave learned details on concerning the GPS (carrier-phase) relative positioning, GPS errorsources, and relevant processing aspects such as parameter estimation. Proper planning of theobservation is important for example to reserve the transportation for the observation day,reserve and check for the GPS instruments, refer the GPS almanac that tells us about the numberof satellites, DOP¶s and satellite coverage in the sky. Besides that, mission planning can makesour job easier and faster. After I have done this assignment, my ability to plan work, use timeeffectively and meet deadlines has been improved. Moreover, team work is very important, aswe able to work in a team and liaises at all levels. We finally can complete our missionsuccessfully. Our communication skills also have been improved.

Overall, this tough assignment is really helpful especially when it requires the students totheir own report. A little bit of force may push the students to do some effort for their own sake.Without realize that this assignment also bring a lot of input to the students.

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Real Time Kinematic (RTK) Concept

The use of reference station networks has become the ubiquitous solution for highprecision satellite positioning applications. The main systematic errors affecting the RTK roverperformance are multipath, atmospheric and ephemeris errors. Whereas single base RTK islimited with respect to the distance between reference and rover the network RTK approachoffers the possibility to increase the coverage area. It ideally leads to a situation in which thepositioning error is independent of the rover position in the area of the network.

One technique proven in production systems for network RTK is the Virtual ReferenceStation (VRS) paradigm. It calculates network corrections for systematic errors based on real-time data from all reference stations, and simulating a local reference station for the user. Thus,the errors cancel out better than by using a more distant reference station.

One major effect from the application of VRS can be seen as a significant reduction ofthe temporal correlation of the ionospheric residual errors. Autocorrelation functions respectivethe autocorrelation time constants show this clearly. Improvements for multipath, troposphericdelay and ephemeris errors are achieved by VRS techniques, too. Taking the changes in the errorcharacteristics into account, RTK systems could benefit even more from the use of referencestation networks.

GPS Heighting Concept

Nowadays the GPS technology is widely used for many kinds of geodetic surveys, forvarious purposes. It is possible to reach millimeter horizontal relative accuracy levels over tens,or even hundreds of kilometers. However, from well-known reasons, the vertical GPS accuracy

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The heights determined by GPS are related to the WGS-84 ellipsoid, while levellingheights (orthometric height) are related to given vertical datum, which is defined physically.Limiting for GPS absolute height accuracy is the exact knowledge of the local (quasi) geoid.Relative GPS heighting is influenced also by many factors. Reduced scheme of observation intriplets may be used to mitigate some periodical noise components in measured heightdifferences. The scheme was practically tested in the campaign focused on determination of thequasigeoidal section from the differences of GPS and levelling heights. Further the scheme wasapplied by measurements of levelling sections in Sněžník network. Relative GPS heightdifferences were measured effectively and with improved accuracy here.

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m To expose the students about the uses of RTK surveying technique in GPS surveying.

m To collect the topography data in area of Padang Kawad UTM to do the topography

mapping.

m To produce a topography map that consist of the topography surface and the contours.

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Location: Padang Kawad UTM

Date: 10th September 2009

Time: 4pm ± 6pm

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2 GPS receivers Unistrong E650R 2 Controllers Unistrong E650R 2 Rods

1 Tripod 1 Cable 2 Antennas

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m Static (mode) and RTK rover GPS surveying technique.

m 1 receiver as base station at Atomic Point (Padang Kawad UTM). m 1 receiver as rover that collect data of topography. m Both receivers are communicating using a radio link.

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m Make a mission planning. m Set the observation date and time. m Reserve the transportation on the observation day. m Reserve two (2) units of dual frequency GPS receivers on the observation day.

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Base Setup

1m Set up base station at Atomic control point (Padang Kawad UTM).

2m Set up also the antenna of the radio link at the both receivers (base and rover RTK). 3.m Key in known coordinate of that point (Padang Kawad). 4.m Connection between devices was set up. 5.m When all the conection was success,we can start to collect data (topographic data) using rover RTK. 6.m Make sure the ambiguity solution is fixed and not a float solution.This is because the ambiguity was not solve,thus the position is out when there are float solution. 7.m When doing the rover surveying, make sure the PDA and the rover are not too far away because conection can be loss.(we used a bluetooth connection) 8.m Avoid shady or obstruction area because this may cause loss of sattelite signal. 9.m Download all the data that have been collected by the rover and used Filter software to download the rover data.Then the data was processed using Microoft Excel, TTC and Surfer Software.

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Using Microsoft Excel and TTC:

1.m After downloading process was performed, we obtain the data of the coordinate system in geographical coordinate. The coordinate need to transform to RSO coordinate in order to use in suffer software.2.m The data was opened in Microsoft excel.

3.m The coordinate which is in decimal point was changed in degree, minute and second by using a converter.

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Using the SURFER Software

1.m SURFER software was used to generate the topographical surface and contour.2.m

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3.m Next, minimize the worksheet and maximize the plot document.4.m Go to Grid > Data and open the topo data to set up the Data Column, Gridding Method and the Output Grid File. We use Kriging method as the Gridding Method.

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6.m To display the contour, go to Map and click Contour Map.

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8.m Our final result which we combined the topographic surface with the contour is shown as below in Surfer Software:

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7.1 All RAW data from Rover RTK receiver will be transfer to Microsoft Excel and the result is we get the coordinate of all points that we have collected from the survey. The coordinates are given in Geographical coordinate (Lat, Long, h) and in Cartesian coordinate (X, Y, h). There are also consist of Horizontal RMS, Vertical RMS, DOP, number of satellites, GPS week and GPS time in second of week for every points.

7.3 The coordinates in RSO system will be export to Surfer Software to generate the topographic view and the coordinates in Surfer are shown as below:

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7.4 The results of 3D topographic surface and the contour that have been generated in Surfer Software are shown as below:

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m m From the raw data of RTK rover measurement, the coordinates are given in Geographical coordinate (Lat, Long, h) and in Cartesian coordinate (X, Y, h). There are also consist of Horizontal RMS, Vertical RMS, DOP, number of satellites, GPS week and GPS time in second of week for every points. m However, we cannot use both of the coordinates system, but we just use the coordinates in Geographical system which based on GPS satellite measurement that refers to the WGS84 datum.

m We have to convert the Geographical coordinates to RSO coordinates in order to map the topographic surface and basically the mapping process require the coordinates in RSO form which is in Northing and Easting. m We use the RSO coordinate system to generate the topographic surface as it can be easily to imagine based on the real Earth.

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m Besides that, the height (h) is referring to the Ellipsoidal height not as the Orthometric height (H). Hence, the height value in ellipsoidal height must be converting to orthometric height in order to generate the contours that refer to mean sea level height. m In Surfer Software, the topographic map is generate by interpolation of the coordinates for each points and the contours is generate by interpolation of the value of orthometric height for every single point.

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m The differences in colours of the topographic image are due to the difference in height of the topography surface on the real Earth. m The green layer in the topographic image shows that the lower altitude of the earth surface which is about 12m above mean sea level, the yellow and chocolate show the mid altitude of the earth which about 12m ± 16m above mean sea level and the highest altitude that is about 16m ± 20m above mean sea level are shown in light blue and blue colour.

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m We have done about 44 points on our fieldwork.m

m There are hilly and a flat area around our location, so we pick both of them but mainly we take a hilly area.m m We also make sure that DOP (dilution of precision) are fairly low to ensure that our position is good.m m We also make sure the availability of the satellite during collecting data.m m The ambiguity must be resolved when float happened so the receiver will reinitialized the ambiguity during the survey.m

" 86'5$m m During the field work, PDA showed that there is floating solution and cannot be fixed although already in a clear area. m We took until 3 hour to perform the fieldwork because there have some problem with PDA battery. m The PDA`s battery has some problem, the battery can only hold for a several minutes. Sometimes it can hold longer and sometimes when we recharged it, it still the same. m We must walk a little bit far from the base station to find hilly area. m There is only one equipment, so it¶s difficult to us to do the work because not all groups consume same work time. m Sometimes the PDA showed the RTK is not available. m Due to our lack understand in using the PDA, we have to manually switch on the Bluetooth function.

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Using GPS, doing a topographic map become much easier and consume less time compareto the conventional method. Our map also more accurate because we use RTK to locate ourpositions. In real working atmosphere, we only need a lot less people doing topographic mapcompare with the conventional method.

Although this method is good and fast, it also has its own weak point. For example, wecannot do this RTK method at sheltered area, between buildings, or in the middle of the jungle.We used isk1, isk2 and isk3 as our points to create a base line. Isk 1, isk2 and isk 3 are CORS,the measurement are done 24 hours a day, 7 days a week in a real time, so its position is soaccurate and good. RTK method use carrier phase measurement to determine point positioning.

However, RTK is not a perfect system which it¶s still has its own defective and weakness.RTK let us plotting map smoother than the conventional method. Lots of software can be uselike TTC, Surfer and TGO in making the map.